They're inside solid rock down there, same deal for our tunnels between Manhattan and LI or the mainland. They just go right down into the bedrock.

Of course, np

Having a therapist who knows what they're doing help you unpack some trauma safely and thoroughly, vs your friend who may try to do the same but lacks the experience and training (or maybe is just smoking weed and chilling). Not to mention, in a clinical setting they may be able to give you something if the experience becomes overwhelming.